Object assignment and pointers

Question

I am a little confused about object assignment and pointers in Ruby, and coded up this snippet to test my assumptions.

class Foo
    attr_accessor :one, :two         


        

Answer 1

There are a lot of questions in this question. The main thing to know is assignment never makes a copy in ruby, but methods often return new objects instead of modifying existing objects. For immutable objects like Fixnums, you can ignore this, but for objects like arrays or Foo instances, to make a copy you must do bar.dup.

As for the array example, foo += is not concatenating onto the array stored in foo, to do that you would do foo.concat(['a']). Instead, it is making a new array and assigning foo to that. The documentation for the Array class mentions which methods mutate the array in place and which return a new array.